1. Field of the Invention
This invention relates generally to water filtration systems and, more particularly, to a modular multi-stage filtration apparatus for selectable filtering modes and scalable capacity.
2. Statement of the Problem
Most households and businesses that receive water from a municipal water supply or other public waterworks depend totally on the waterworks"" filtration system for ensuring the purity of the water. For purposes of this description xe2x80x9cpurityxe2x80x9d means acceptable, non-hazardous amounts of particulate matter, bacteria, minerals, organic and inorganic compounds and chemicals. There are shortcomings, however, in the filtration and purification systems used by many public waterworks. Many arise from the large water volume and the wide, complex distribution network that public waterworks must have to supply the water needs of users ranging into the millions. The large water volume limits the level and type of filtration that can be used. The distribution network frequently introduces new impurities downstream of the public waterworks filters. A related shortcoming is that the distribution network, by having such a large number of water passages extending over significant distances, is susceptible to influx of impurities and contaminants. Still another shortcoming, which is inherent in public waterworks, is that all of the water is filtered the same for all users.
Another issue relating to public waterworks, both their distribution network and their filtering and purification capabilities, is the increasing threat of biological or chemical agents being introduced into the water supplies, either for purposes of terrorism or simple random acts of malice. As a result, there is a need for a water purification and filtering system that can quickly incorporate state-of-the-art filtering features to reduce or eliminate new threats. It is estimated, however, that many public waterworks may not be able to meet these needs. One reason for this failure is the large volume of water that the public waterworks must deliver, which dictates correspondingly large filtration systems. Such large filtration systems are typically costly to modify or add additional stages to. A related issue is that the costs for some filtering modifications, in view of the scale, are rendered impractical. Further, public waterworks generally include a very large scale distribution network. In addition to creating an inherent susceptibility to introduction of impurities and contaminants, such a network significantly increases the susceptibility to chemical and biological agents being introduced downstream of their central filters.
Numerous types of water filtration systems, their component apparatus, and filtration methods employed within the apparatus are known in the art. Known water filtration systems include xe2x80x9cpoint of usexe2x80x9d water filters, which are installed local to a potable water outlet dedicated to a single user, or single apparatus or appliance. Examples include, but are not limited to, water faucets for a kitchen or bathroom sink, a shower or bathtub, a water fountain, and a clothes washing machine. Other known water filtration systems include xe2x80x9cpoint-of-entryxe2x80x9d water filters, which are located and installed to filter the water entering a house or business facility, prior to the water flowing into the distribution pipes typically providing water to the above-identified point of use outlets. The entry at which the xe2x80x9cpoint of entryxe2x80x9d filter is installed is typically fed by the municipal water supply or a well. The two types of filter systems typically have different capacity requirements, filtering performance, maintenance requirements, and cost, such that an apparatus or system optimized for one may not be optimal for the other.
Multiple stage filters are known in the art of water filtration, both for point of entry and point of use. A typical multiple stage point of use water filtration system includes multiple filter containers or cylinders receiving water from a diverter valve attached to a sink faucet, water supply line to the sink faucet, or to another plumbing connection dedicated to the point of use outlet. The diverter valve typically introduces the unfiltered water to the filter media inside the cylinders, from which it is eventually dispensed through a spigot. The filter cylinders are typically, but not necessarily, oriented vertically with respect to the earth. If the apparatus is visible and accessible, the spigot may be located on, for example, a housing of the apparatus. An example water filter having such a spigot is the kind located on a sink counter, which is commonly referenced as an xe2x80x9cabove-the-counterxe2x80x9d model. The spigot may be separate from the filter apparatus, an example being a second faucet connected to an outlet port of the filter by a feed line, which is commonly referred to as an xe2x80x9cunder-the-counterxe2x80x9d model.
A typical point of entry water filter is also multistage, employing multiple cylinders similar to those used within a point of use apparatus, sized for higher water flow rates and higher treatment capacities.
Regardless of its mounting location, a typical known or existing multistage water filtration apparatus includes an integrated set of filter containers or cylinders, or a fixed arrangement or sequence of filters. The type having an integrated set of filter containers has one or more predetermined configurations of filters, not changeable by the end user, and requires periodic replacement of the entire set, as a unit. The integrated filter set also does not have provision for controlling the sequence of filters that the water flows through, or means for the end user to select various sub-sets of the filters to obtain customized filtering.
An example of a filter having individual cylinders which are themselves replaceable is disclosed by U.S. Pat. No. 6,080,313, issued to Kelada. As seen from the example patent, the filter units, although individually replaceable, have a fixed configuration. The fixed configuration of this design limits its ability to optimally target the characteristics of a particular water source, and its ability to adapt to changes in water sources or source characteristics.
The present invention advances the art, including overcoming above-identified shortcomings in the prior art, and provides additional features and benefits, with a modular water filter system and method for filtering based on same.
A first example of an embodiment of this invention includes a bracket and a plurality of canister mount diverter valves, each mounted to the bracket. Each canister mount diverter valve has a receptacle, a valve intake port, a filter feed port, a filter output port, a valve output port, and a valve apparatus switchable between a first mode and a second mode. The first mode provides a filter feed passage from the valve intake port to the filter feed port and a filter flow receiving passage from the filter flow receiving port to the valve outlet port. The second mode provides a bypass water passage from the valve intake port to the valve outlet port, while cutting off the flow between the valve inlet port and the filter feed port and between the filter flow receiving port and the valve outlet port.
The example first embodiment further includes a plurality of canisters, each having a housing surrounding a contained volume. The housing has an engagement structure engaged with the receptacle of a corresponding one of the plurality of canister mount diverter valves. The contained volume of each canister includes a filter material, an inlet port opening at one end on an exterior surface of the housing and opening to the interior volume at another end, and an outlet port opening at one end on an exterior surface of the housing and opening to the interior volume at another end. The inlet port cooperates with the filter feed port of the corresponding one of said plurality of valve bodies to establish a water passage from the valve inlet port to the interior of the filter canister, and the outlet port cooperates with the filter flow receiving port of the one of the plurality of valves to form a water passage from the interior of the canister to the valve outlet port.
The example first embodiment further includes a first interconnect water passage extending from the valve output port of a first of the plurality of canister mount diverter valves to the valve input port of a second of the plurality of canister mount diverter valves. In addition, a final water passage extends from the valve output port of the second of the plurality of canister mount diverter valves to a final filtered water tap having an on-off valve.
The example first embodiment still further includes a first of the plurality of filter canisters engaged with the first of the plurality of valve bodies and a second of the plurality of filter canisters engaged with the second the plurality of valve bodies. In the example embodiment, at least two of the plurality of filter canisters have substantially identical engagement structures whereby each is interchangeable with the other with respect to engagement with at least two of said valve bodies.
A further example embodiment is in accordance with the above-summarized embodiment, further including an intermediate on-off tap connected at one end to an intermediate output spigot and connected at another end to a water tap-off between the valve outlet port of the one of the canister mount diverter valves and the inlet port of another of the canister mount diverter valves.
Another example embodiment of the invention is in accordance with any of the previously summarized embodiments, and further includes an ultraviolet sterilizing apparatus, having an input port and an output port, the input port connected through a water line to the exterior output port of any of the canister mount diverter valves.
Another aspect of the invention includes one of the filter modules having a second output port formed in its housing, the second output port having one end opening on an exterior of filter module""s housing and having its other end opening to a waste output portion of the filter medium. This aspect further includes a water passage connecting the second output port to a external water drain.
A further aspect of this invention includes a reservoir storage tank having an input/output port connected to the input port of one of the canister mount diverter valves. The reservoir storage tank is connected to store a capacity of water when the on-off valve of the final filtered water output tap is closed and to output, at a predetermined pressure, the stored water into the input port of the canister mount diverter valve to which it is connected when the on-off valve of the final filtered water output tap is opened.
A further aspect of the invention forms at least one of the canister mount diverter valves having a diverter valve with a movable member and an actuator for acting on the movable member such that when the canister mount diverter valve is not engaged with a filter canister the actuator moves the movable member to open the bypass water passage from the valve input port to the valve outlet port, to block water from flowing between the valve inlet port and the filter feed port and from flowing between the valve outlet port and the filter flow receiving port.
Each of the above aspects of the invention provides a multi-stage modular water filtration system, adaptable to point-of-use or point-of-entry service, formed of a plurality of interchangeable filter canisters engaged within an interconnected plurality of canister mount diverter valves. Each filter canister contains a specific filter medium, selected for the user needs of the installed environment. The interchangeable feature of the filter canisters provides for an unlimited variety of filter configurations using the same plurality of canister mount diverter valves. This feature provides the capacity for performing a specific range of filtration functions, thereby allowing the user to select and configure a water filtration system that is directly targeted to filtration issues specific to a particular water source.
Moreover, the filter media in each filter canister can be upgraded or enhanced in composition, making individual filter canisters scalable to the treatment of higher concentrations of particular water contaminants. Still further, the aspect having at least one diverter valve provides multiple treatment grades of filtered water on demand, from a single source of water.
It is therefore a principal object of the invention to provide a modular multi-staged water filtration system, each module being a canister mount diverter valve with an engagement receptacle for filter canisters having a common outer engagement structure. The canisters can be replaced and rearranged without shutting off the water supply. One system can operate without all of the diverter valves having a filter canister installed, thereby allowing a common system design to be used for a variety of applications.
It is another principal object of the invention to form the engagement structure of the canister mount diverter valve and filter module engagement structure to have a twist-tap method of attachment. This renders each filter module easily attached to, removed from, or interchanged with another module, without interruption to the water flow though the apparatus.